when content instances aka modules are deleted from the content catalog we need a feature specific way to delete content for the feature that is associated with the deleted module this a a base class for features to implement. The FeatureDefinition.DeleteProvider must correspond to the name of the feature specific implementation, so that the system can invoke the correct ContentDeleteHandlerProvider

The purpose of this provider is just to make sure there is always at least one provider in the collection even if we have to disable the search index by removing the other providers

Features may be installed separately from the core of mojoPortal and may have foriegn key relationships that can cause errors if a site is deleted. Feature implementors should either implement cascading deletes for their feature content or implement a SitePreDeleteHandlerProvider that deletes all data for the feature related to the the passed in siteId. These providers will be called just prior to actual site deletion. It should be noted that by default site deletion is disabled in Web.config to prevent accidental deletion of a site by users. It should be enabled only temporarily to delete a site on purpose then set back to diabled. The provider implementations can assume that the deletion is intentional.